Photographic color film and the method of use in color printing



Aug. 11, 1964 R. R. WALDHERR PHOTOGRAPHIC COLOR FILM AND THE METHOD OF USE IN COLOR PRINTING 2 Sheets-Sheet 1 Filed Jan. 6, 1961 jazzed M Adarrfiw a w mm m A m w 4 n H m 3 w w d 7 i 2 H 5 J j 1 (.B 1 9 1 Aug. 11, 1964 R. R. WALDHERR 3,144,333

PHOTOGRAPHIC COLOR FILM AND THE METHOD OF USE IN COLOR PRINTING Filed Jan. 6, 1961 2 Sheets-Sheet 2 United States Patent 3,144,333 PHQTOGRAPHKQ QGLUR FILM AND Tm METHOD 0F USE 1N 601.011 PTHNG Robert R. Waldherr, 4980 Marine Drive, Chicago, Ill. Filed Jan. 6, 1961, Ser. No. 81,064- 5 Claims. (Cl. 96-62) The invention relates to improvements in the manufacture of photographic color film for the printing trade and more particularly to a novel multi-layered photographic color film and to the method and means for economical quality control and predetermination of final reproduction results prior to the reproduction process in multi-color printing.

Known types of films for use in producing photographic pictures in natural color consist of a film base or transparency having superimposed thereon, one on top of the other, layers of silver halide gelatin emulsions each containing an organic colorless dyestuil component capable of reacting with a further component to product a dyes'tufi image. Such films are primarily intended for the purpose of rendering a colored picture of a snapshot useful solely by the amateur and commercial photographer.

The conventionally accepted procedure employed in various mediums of reproducing colored copy in color on paper, by means of ink carrying press plates or cylinders, wherein the subject is photographed through blue, green and red filters on panchromatic photographic material to obtain three separate color negatives and in addition to which a black negative is shot, either without lfiter or through a combination of filters, or through any of the K type filters. Such negatives are either masked, retouched or both.

From such negatives, either screen positives or continuous tone positives are made directly on a copper plate (as in the case of letter press) in which case a good deal of additional color correcting is done by means of going through various stages of copper etching. In the case of screened positives (as in offset printing) any subsequent color corrections is performed by cyanide dotetching of the screened color positive.

In the case of rotogravure, the continuous tone positives are color corrected by both reducing the density of local areas by the application of reducers (such as a ferricyanide solution) and by increasing the density of local areas through the application of dye. Following this, a screened negative is made from the retouched positive. From the screened negative, a screen positive is made by contact and both positives are then alternately printed in register on a light sensitive gelatin coated tissue (called carbon-tissue in the trade). This tissue is in turn transferred to a copper-plated cylinder which in turn is intaglio etched.

The preparations necessary to transfer a screened image tone zinc-plate (as in offset printin or to a final copperplate (as in letter-press) are similarly involved and up to the time the first proof in color on paper is obtained from the press, all the costly and time consuming work has been done on the potential representation of the color image in a colorless image of continuous tones or dots.

In the practice of the previously described conventional processes, any errors in coloring or registry are not detected until final production of a colored copy in color in a proof press or production press. All masking, as well as positive or negative retouching, depends entirely on judgment of colorless values (various densities of grays) with the result that there is a great deal of over and under correction and costly reproduction of etched plates.

The laminated photographic color film of the present invention has for one of its purposes the economical and time saving quality control of color for the printing industry, which control is effected at the beginning of the job. More particularly, the film of the present invention is comprised of three thin transparent carrier films. A layer of color dyestuff emulsion is carried on each carrier film and the whole is joined together firmly and in a manner to permit separation easily and quickly for a purpose to be discussed presently. A filter layer is interposed between the top and middle carrier films. Further, all but the uppermost emulsion bearing carrier film are suitably punched, perforated or otherwise provided with means for insuring evacuation of atmosphere from between them and aifording tight surface to surface contact between the carrier films and/or with associate film and for adherence to a vacuum back camera.

The novel multi-layered film may be separated before the developing process and, after being developed, each carrier film affords means for obtaining Visual proof of final reproduction results to be obtained from any given copy material but at the very outset of the reproduction process. As hereinabove noted, such visual proof was obtained only at the very end of the processing, as in a proofing press or in a production press.

Such visual proof is now made possible by arranging the processed color carrier films on a light box to provide visual proof. Any indicated color correction can then be made directly on any one or all of said carrier films with color dyes, or superimposed colored overlay film. The original carrier films, whether retouched or not, may then be used to make a set of negatives or, if the required corrections are of any magnitude, a second color film or films may be made from the corrected color carrier film or films, and used in its stead for making the negatives.

More particularly, the use of the improved multilayered film permits all color corrections to be completely photomechanically controlled as to necessary adjustments at the initial stages of reproduction, thus eliminating retouching time and cost and the uncertainties accompanying same when conventional processes are followed. In fact, as stated hereinabove, critical correction requirements can be detected at the first stage of the process by use of a light boX or the like and mechanically controlled by increasing or decreasing the color densities in local areas all without the need of expensive equipment.

The structure and means by which the above noted and other advantages of the invention are attained will be described in the following specification, taken in conjunction with the accompanying drawings, showing a preferred illustrative embodiment of the invention, in which:

FIG. 1 is a sectional view, greatly enlarged, of the multi-layered film of the present invention.

FIG. 2 is a representative illustration of the three color film shown in FIG. 1, exposed and illustrating a representative color image.

FIG. 3 is a view similar to FIG. 1 but showing the carrier films separated.

FIG. 4 is illustrative of each of the color carrier films shown in FIG. 3, after exposure and processing.

FIG. 5 is a view illustrating a series of black and white negatives, one made from each color carrier film shown in FIG. 4.

FIG. 6 is a perspective view, greatly enlarged, of a normal exposed black and white film bearing the image and white plate finally produced and ready for use in the press.

The novel multi-layered film generally indicated at F in FIG. 1 is comprised of three carrier films each coated with sensitized color emulsion and dye couplers and combined in a manner to permit their being separated easily and quickly before being processed or simultaneously. Specifically, the multi-layered film F is comprised of three carrier films 12, 13 and 14, each comprised of a thin layer of polystyrene, polyester, or other suitable clear transparent plastic material, and each coated with a silver halide gelatin emulsion containing an organic dyestulf component. More particularly, one of said carrier films, such as the film 12, is coated on one surface with a red sensitive emulsion 15 with a blue dye coupler; another carrier film, such as film 13, is coated with a green sensitive emulsion 16 with a red dye coupler and the third carrier film 14 is coated with a blue sensitive emulsion 17 with a yellow dye coupler.

These three coated sensitized carrier films are superimposed one on the other, in the following order, from bottom to top, the red sensitive emulsion carrier film 12, the green sensitive emulsion carrier film 13 and finally the blue sensitive emulsion carrier film 14. A yellow filter 18 (FIG. 1) is interposed between the green and blue sensitive emulsion carrier films 13 and 14 respectively, and the laminae is joined into an integral whole by the application of a suitable adhesive 19 on the complemental edges of said films.

Suitable means is provided in the composite film F to adopt all laminae thereof to be held in tight surface to surface contact during exposure. Such means may comprise a series of perforations 21 in each film excepting the uppermost film 14 and so arranged with respect to one another that when the film F is placed in a camera equipped with a vacuum frame, the negative pressure applied to the back surface of the composite film is effective in a positive manner on each layer thereof to eliminate all atmosphere from between the carrier films and hold them in tight face to face perfect contact during exposure. After exposure the composite film then is processed in the usual developing and fixing component and the three color emulsion carrier films, which are now yellow, red and blue, as shown at 22, 23 and 24 in FIG. 4, now serve as individual color separation positives in their intended colors.

In order to proof check the color and match before preparation of the usual black and white positive films that are used in the etching process, the values of the colors produced on the carrier films 12, 13 and 14 can be compared with chart values while on a light box and should any corrections be required same can be effected by local retouching of the individual color films with dyes of the same color. To accomplish extremely complicated color corrections, such as complex color patterns, a set of negatives can be made on thin-base films of the same type as that used in the original three color separation film but in individual colors. Such colored supplementary films can then be superimposed wherever additional color is needed, while regulated and measured color reductions can be made in the making of the second negative set of color film. Then, the color negatives are photographed in a manner more particularly described hereinafter, to produce black and white negative films 25, 26 and 27 respectively, (FIG. 5) from which positive prints 25', 26 and 27' (FIG. 8) are made.

The process herein disclosed includes preparation and use of two black negatives of the subject picture which will now be described. One of the black negatives 28, illustrated in FIG. 6 is normal exposed and is developed for maximum light tone contrast so that three-quarter tones and solids are under exposed and clear. Preferably, it should have a shadow densitometer reading of 0.40 and a hilite reading of 1.80, or an average range of 1.40.

The other black negative 29 (FIG. 7) is overexposed and is developed for maximum shadow contrast, the light and middle tones being closed up. This negative is intended to give maximum separation in the solid and threequarter tone areas, hence it is overexposed and is slightly overdeveloped. Preferably, this negative should have a shadow densitometer reading of 0.60 to 0.70 and the white should read 2.20 to 2.40 or an average range of 1.60. Its characteristic should be a more than normal amount of separation of the black shadow detail, falling off to normal in the three-quarter tones and complete closing up of light and light middle tones.

From negative 28 a skeleton positive 34 (FIG. 8) can be made or should the particular copy because of its peculiar complexity require a fully color corrected key positive, the necessary photomechanical masking corrections of this negative can be made, the results of such corrections again can be checked with the visual three colors.

The negative 29 can be used either as a so-called shadow burner mask during the original three-color separation exposure if a skeleton key is to be used, or as a part exposure mask to reduce under-color in the making of a second set of negatives from the corrected individual color films in instances where it is advisable to produce a highly accurate reproduction.

As noted hereinabove, the color negatives 12, 13 and 14 are photographed to produce the negative black and white films 25, 26 and 27, respectively. This may be accomplished in the following manner:

The yellow color film is photographed, with a blue filter, such as Wratten #47 or #C5. Similarly, the red color film is photographed with a green filter, such as Wratten #28 or #13, whereas the blue color film is photographed with a red filter such as Wratten #25, so as to produce the requisite three black and white negative films 25, 26 and 27. Preferably, the black and white key film 29 (FIG. 7) is thrust into the exposure path for a predetermined period of time to increase the exposure of such areas in the color negatives where the deeper blacks of the black positive ultimately will print, thereby reducing the amount of under-color in each individual color.

Four printing plates 35, 36, 37 and 38 (FIG. 9) are then prepared, one from each positive film 25', 26 and 27; and one from the key black and white positive film 34, by the usual etching processes.

By lug perforating all film, preferably at the margins thereof, as at 39, perfect register is secured easily and quickly and production is speeded up considerably.

From the foregoing description it is believed that the nature of my invention and the manner in which it is to be carried out will be readily apparent to those skilled in this art.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A process of producing etched color plates which comprises photographing a multi-color image on a photographic element constructed of at least three transparent plastic films, each film being equipped with an imageforming silver halide gelatin emulsion layer on each face thereof and arranged in superposed relation, said layers being sensitive to distinct and substantially exclusive spectral regions, said films and layers being arranged into a laminate characterized by the substantial absence of internal air, each image-forming layer having incorporated therein a different coupler dye material producing, upon development, a positive having the coupled dye color in areas exposed to radiation in the spectrum of said dye color, separating the said films while retaining therewith the emulsion layer with which each film is equipped, developing said layers to produce a positive color image of a different color on each film, producing a black and white negative of each developed film, and producing etched plates from each black and white negative.

2. A process of producing etched color plates which comprises photographing a multi-color image on a photographic element constructed of at least three transparent plastic films, each film being equipped with an imageforming silver halide gelatin emulsion layer on each face thereof and arranged in superposed relation, said layers being sensitive to distinct and substantially exclusive spectral regions, said films and layers being arranged into a laminate characterized by the substantial absence of internal air, each image-forming layer having incorporated therein a dilferent coupler dye material producing, upon development a positive having, the coupler dye color in areas exposed to radiation in the spectrum of said dye color,

separating the said films while retaining therewith the emulsion layer with which each film is equipped, developing said layers to produce a positive color image of a different color on each film,

producing a black and White negative of each developed producing a black and white positive of each negative,

and

producing etched plates from each black and white positive.

3. The process of claim 2 in which the color values in said developed layer are corrected prior to producing a black and white negative therefrom, the correction being achieved through retouching and superposing an overlaid film of the same color as the positive to be corrected.

4. The process of claim 3 in which said black and White negative is corrected prior to producing a black and white positive therefrom through providing a second negative in the same color as the negative to be corrected.

5. In a process of producing color printing plates wherein each plate is adapted to provide one color of a multi-color image, the steps of:

photographing a mutli-color image on a photographic medium comprising at least three transparent polyester films, each film being equipped with an imageforming silver halide gelatin emulsion layer on one face thereof and arranged in superposed relation, said layers being sensitive to distinct and substantially exclusive spectral regions, said films and layers being arranged into a laminate characterized by the substantial absence of internal air, each imageforming layer having incorporated therein a different coupler dye material for producing, upon development, a positive having the coupler dye color in areas exposed to radiation in the spectrum of said dye color, whereby a plurality of individual color positives are provided,

preparing a key black and White positive film of the multi-color image,

separating the exposed polyester films, each still retaining its associated emulsion layer,

developing each of said layers to provide a single color positive on each polyester film,

preparing a black and white negative from each color positive,

preparing a black and White positive from each black and white negative, and

preparing a printing plate from each black and white positive film and said key black and white positive film.

References Cited in the file of this patent UNITED STATES PATENTS 1,499,230 Lage June 24, 1924 1,612,079 Von Tolnay et al. Dec. 28, 1926 1,785,997 Blecher Dec. 23, 1930 2,088,145 Von Biehler July 27, 1937 2,167,732 Verkinderen Aug. 1, 1939 2,182,814 Marasco Dec. 12, 1939 2,208,754 Eggert et al July 23, 1940 2,242,747 Frankenburger et al Mar. 20, 1941 2,415,442 Rackett Feb. 11, 1947 2,615,807 Umberger Oct. 28, 1952 2,671,020 Grumbine et a1. Mar. 2, 1954 FOREIGN PATENTS 205,807 Great Britain Nov. 20, 1924 

1. A PROCESS OF PRODUCING ETCHED COLOR PLATES WHICH COMPRISES PHOTOGRAPHING A MULTI-COLOR IMAGE ON A PHOTOGRAPHIC ELEMENT CONSTRUCTED OF AT LEAST THREE TRANSPARENT PLASTIC FILMS, EACH FILM BEING EQUIPPED WITH AN IMAGEFORMING SILVER HALIDE GELATIN EMULSION LAYER ON EACH FACE THEREOF AND ARRANGED IN SUPERPOSED RELATION, SAID LAYERS BEING SENSITIVE TO DISTINCT AND SUBSTANTIALLY EXCLUSIVE SPECTRAL REGIONS, SAID FILMS AND LAYERS BEING ARRANGED INTO A LAMINATE CHARACTERIZED BY THE SUBSTANTIAL ABSENCE OF INTERNAL AIR, EACH IMAGE-FORMING LAYER HAVING INCORPORATED THEREIN A DIFFERENT COUPLER DYE MATERIAL PRODUCING, UPON DEVELOPMENT, A POSITIVE HAVING THE COUPOLED DYE COLOR IN AREAS EXPOSED TO RADIATION IN THE SPECTRUM OF SAID DYE COLOR, SEPARATING THE SAID FILMS WHILE RETAINING THEREWITH THE EMULSION LAYER WITH WHICH EACH FILM IS EQUIPPED, DEVELOPING SAID LAYERS TO PRODUCE A POSITIVE COLOR IMAGE OF A DIFFERENT COLOR ON EACH FILM, PRODUCING A BLACK AND WHITE NEGATIVE OF EACH DEVELOPED FILM, AND PRODUCING ETCHED PLATES FROM EACH BLACK AND WHITE NEGATIVE. 